1. Field of the Invention
The present invention relates to an optical information reproducing and recording apparatus such as a CD player, an MD player mounted on a vehicle such as an automobile.
2. Description of the Related Art
An optical information reproducing and recording apparatus such as a CD player, an MD player mounted on a vehicle such as an automobile is exposed to a thermal environment which intensely changes by seasons or the weather. Accordingly, in general, a temperature sensor is mounted in the inside of the apparatus and when the temperature in the inside of the apparatus is abnormally elevated or lowered, the temperature sensor detects this phenomenon and automatically stops the operation of the apparatus thus preventing breakage and deterioration of quality of devices inside the apparatus due to the abnormal temperature.
In general, in an optical information reproducing apparatus such as a CD player which reproduces information recorded on an optical recording medium, laser beams are irradiated on a recording surface of a disc using optical reading means including a light source such as a laser diode which optically reads the recorded information and extracts modulated components contained in the reflected light so as to reproduce the recorded information.
However, because the laser diode which constitutes a light source is a semiconductor , there has been a problem that the laser diode breaks in a short time, when the laser diode is operated under a high temperature.
In view of the above, a conventional optical information reproducing apparatus adapts a constitution in which the temperature of the optical reading means is monitored and when the temperature exceeds a given temperature, the operation of the optical reading means is stopped. Under such a constitution, when the operation of the optical reading means is stopped and the temperature is lowered to a value below a given temperature, the operation will start again. However, due to a coupled effect of the heat generated by the re-operation and the preheat remaining in the apparatus, the temperature of the optical reading means exceeds the given temperature immediately after the operation so that the operation must be stopped again. Such starting and stopping operations are cumbersome.
On the other hand, since an optical information reproducing and recording apparatus such as an MD player performs not only the reproduction of the information but also the recording of the information and hence, it is necessary to drive a laser diode with a larger electric power at the time of recording compared with the electric power at the time of reproducing. The generation of heat of the optical reading means including the light source such as the laser diode largely differs between the time of recording and the time of reproducing. Accordingly, when an optical information reproducing and recording apparatus such as the MD player is mounted on a vehicle, in view of the severe change of environmental temperature derived from mounting of the apparatus on the vehicle and hence, a delicate temperature monitoring which considers the difference of heat generation between the time of recording information and the time of reproducing information becomes necessary.
An optical information reproducing and recording apparatus such as the MD player heats a magnetic film on the surface of a disc, which constitutes a recording medium, at a given temperature by the irradiation of laser beams from the laser diode and simultaneously writes information in the disc by applying a magnetic modulation to the above-mentioned magnetic film by means of an information recording magnetic head disposed adjacent to the disc.
In general, it has been known that when the laser diode is driven under the thermal environment of an excessively high temperature or an excessively low temperature, the quality of a semiconductor which constitutes the laser diode is deteriorated, thus remarkably shortening the lifetime thereof.
In view of the above, to prevent failures derived from the deterioration of the laser diode, the conventional vehicle-mounting-type information reproducing and recording apparatus detects the temperature of the apparatus, particularly the temperature in the vicinity of the laser diode and automatically stops the irradiation of laser beams, that is, the writing of the information when the temperature exceeds a given temperature range.
On the other hand, in an optical reproducing and recording apparatus such as the MD player, when information signal such as music is written in the disc, after the recording of the information signal is completed, a signal(hereinafter called xe2x80x9cadministration signalxe2x80x9d) which administrates the recording conditions such as playing time of the recorded music, the recording order in the disc, the recording area and address in the disc is recorded together with administration signal area on the disc. After recording the information signals, the information reproducing and recording apparatus performs the reproducing and the editing of the music recorded in the disc based on such administration signals. Accordingly, when the administration signals are not written due to some reasons, even when the information signals on the music are wholly accurately written, the reproducing and editing of the music recorded in the disc becomes impossible.
However, in the conventional vehicle-mounting-type information reproducing and recording apparatus, when the temperature in the inside of the apparatus deviates from a given usage temperature range in the midst of writing the music, the writing operation is instantly stopped and the disc is ejected from the apparatus housing so as to prevent the deterioration of the laser diode. Accordingly, the writing of the administration signals can not be performed so that the information signals recorded in the disc when the writing is stopped are wasted whereby the availability of the information recording and reproducing apparatus in operation is remarkably reduced.
It is an object of the present invention to provide an optical information reproducing and recording apparatus which can maintain the reliability of the apparatus even under the severe temperature change and is capable of performing proper operations.
According to the present invention, an optical information reproducing and recording apparatus which records information to a optical information recording medium and reproduces the recorded information includes first signal processing part which processes a input signal and generates a writing signal to the information recording medium, information writing part which writes the writing signal into the information recording medium, information reading part which reads information recorded in the information recording medium and generates a reading signal, second signal processing part which performs signal processing of the reading signal and generates an information reproducing signal, temperature detecting part which detects the temperature of the information writing part and the information reading part, control part which controls operations of the information writing part and the information reading part based on a detected value from the temperature detecting part, wherein the control part performs a control such that the control part allows the operation of the information writing part and the information reading part only when the detected value falls within a first temperature setting range, the control part stops the operation of the information writing part and information reading part when the detected value exceeds a second temperature setting range, and the control part allows the restarting of the operations of information writing part and the information reading part when the detected value falls within a third temperature setting range, and the first to third temperature setting ranges can be set individually with respect to respective operations of the information writing or the information reading.
Further, according to the present invention, an optical information reproducing and recording apparatus which records an information signal in an optical information recording medium together with a administration signal and reproduces the signals includes information writing and reading part which writes the information signal and the administration signal into the information recording medium or reads the written signals by irradiating optical beams to the information recording medium, temperature detecting part for detecting a temperature of the information writing and reading part, control part which controls the writing operation or the reading operation of the information writing and reading part in response to a writing or reading command and based on a detected value from the temperature detecting part, wherein the control part performs a control such that provided that the writing command is supplied to the control part, when the detected value is out of a given set temperature range, the control part stops the writing operation of the information signal and shifts the writing operation to only the writing operation of the administration signal.